The present invention relates to a cross type indicator. More particularly, the present invention relates to a cross coil type indicator constructed in a compact configuration wherein the end part of a wire extending from each coil is fixedly connected to the corresponding pin-shaped terminal by soldering.
Many indicators each including a cross coil type movement section are usually used for vehicles. Specifically, an indicator of the foregoing type is constructed such that a pair of coils for generating magnetic fields orienting at a right angle relative to each other are activated by feeding an electric current thereto of which intensity varies corresponding to a desired measurement quantity, and a magnet rotor is rotated in the direction of the composite magnetic field derived from the foregoing magnetic fields generated by the coils, whereby the measurement quantity is indicated by a pointer adapted to be rotated together with the magnet rotor. In recent years, there is a tendency that various kinds of components such as a calculating unit or the like are arranged peripheral to the movement section of the indicator. For this reason, many compact type indicators of which movement section is constructed in a compact configuration have been practically used at present.
A typical conventional cross coil type indicator will be described below with reference to FIG. 3 and FIG. 4.
The indicator includes a coil bobbin 1 on which a pair of coils 2 are disposed orthogonally to each other, and four posts 3 are caused to stand upright around the outer peripheral part of the coil bobbin 1 in the equally spaced relationship in the circumferential direction with an angle of 90 degrees between adjacent posts 3 so as to allow the coils 2 to be wound about the respective posts 3. Among the four posts 3, a pair of posts 3a arranged symmetrically relative to a rotational shaft 8 to be described later are dimensioned to have a height more than that of another pair of posts 3b. Terminal holding portions 4 each having a pin-shaped terminal 5 extending therethrough substantially in parallel with the posts 3 are integrated with the coil bobbin 1 at the positions located outside of the posts 3. It should be noted that the aforementioned components are accommodated in a case (not shown) for a movement section of the indicator.
As shown in FIG. 4, the end part of a wire extending from each coil 2 is secured to the pin-shaped pin 5 by winding the former about the latter by a few turns, and the wound wire is fixed thereto by soldering it at 6.
Circular disc-shaped magnet rotor 7 having S poles and N poles is rotatably received in the coil bobbin 1, and a rotational shaft 8 is fitted to the central part of the magnet rotor 7 while extending in the axial direction of the coil bobbin 1. While the coils 2 are not activated without any electric current fed thereto, the magnet rotor 7 is freely rotatable about the center axis of the rotational shaft 8. When each coil 2 is fed with an electric current, the magnet rotor 7 is rotationally driven by a predetermined angle.
A spirally extending spring 9 is disposed on the magnet rotor 8 in such a manner that one end of the spring 9 is fixedly secured to the upper end of one post 3a, while the other end of the same is fixedly secured to the rotational shaft 8. While the coils 2 are not activated without any electric current fed thereto and the magnet rotor 7 is freely rotatable, the rotational shaft 8 is returned to a zero position on a dial (not shown) by the resilient force of the spirally extending spring 9.
The movement section of the indicator constructed in the above-described manner is fixedly mounted on the upper surface of a printed circuit board (not shown) molded of a hard synthetic resin by securing the pin-shaped terminals 5 to the printed circuit board. In addition, a dial (not shown) having a light permeable plate attached to the rear surface thereof is placed on the upper surface of the movement section, and a pointer (not shown) is secured to a part of the rotational shaft 8 projected outside of the dial, whereby the indicator is constructed as an instrument unit. Subsequently, the indicator is accommodated in a predetermined case by immovably holding the printed circuit board with the aid of support posts (not shown) for the case.
With the conventional cross coil type indicator constructed in a compact configuration in the above-described manner, each coil 2 is electrically connected to the pin-shaped terminal 5 by soldering the end part of a wire extending from the coil 2 directly to the pin-shaped terminal 5 while winding it about the pin-shaped terminal 5 a few turns. Thus, there is a possibility that a part of the molten solder 6 will flow down to the coil bobbin 1 side along the wire of the coil 2, resulting in the tensile strength of the wire of the coil 2 being remarkably reduced. Another problem is that when a certain intensity of pulling force is applied to the wire of the coil 2, wire disconnection may occur at the position where the molten solder 6 is solidified on the wire. Once wire disconnection has occurred, the indicator fails to operate properly.